| 1. | This paper first research on main technologies used by avs standard , which include prediction , transform , quantization , in - loop filter , and entropy encoding , and then focus on the 2d - vlc entropy coder of avs , which is context - based adaptive coder . this encoder operates on run - level pair , and it uses the type of current block and value of current coefficients to switch vlc code - table . these tables are designed according to the distribution of transformed coefficients , and this way is much better than using only one table to code all residual coefficients in one 8x8 block
本文首先详细研究了avs标准的核心技术,包括预测编码、变换量化、环路滤波器以及扫描和熵编码等,之后重点研究了avs标准中使用的基于上下文的2d - vlc变长编码方法,这种方法编码的是( run , level )数对,同时根据当前编码块的类型和残差系数这两种上下文信息来切换码表,这些码表是预先根据变换系数在不同位置的分布信息设计好的,这样要比只使用一个变长码表来编码块内所有位置上的残差系数的压缩效果要好得多。 |
